Recently, as existing energy resources like oil and coal and the like are expected to be exhausted, much attention is increasingly paid to alternative energy sources which can be used in place of the existing energy sources. As an alternative energy sources, sunlight energy is abundant and has no environmental pollution. Therefore, more and more attention is paid to the sunlight energy.
A photovoltaic module converting sunlight energy into electrical energy has a junction structure of a p-type semiconductor and an n-type semiconductor. When light is incident on the photovoltaic module, an electron with a negative electric charge and a hole with a positive electric charge are generated by interaction between the light and a material constituting the semiconductor of the photovoltaic module. Then, electric current flows while the electron and the hole move.
More attention is now being increasingly paid to a building integrated photovoltaic (BIPV) module which is installed on the ceiling, wall or window of a building and generates electricity. The BIPV module is required to retain not only an original function of electric power generation but also various features. Particularly, since the BIPV module constitutes the building envelope, it is necessary to provide a photovoltaic module having an improved aesthetic feature.